Two of the most dynamic and fastest growing technologies in recent years are wireless communications and the Internet. Wireless access to the Internet is currently available from mobile telephones and from laptop computers, and is being developed for other mobile devices such as personal digital assistants (PDAs). The WAP (and i-mode technology) is a leading contender to provide wireless access to data networks. However there are currently numerous limitations to WAP data access.
FIG. 1 illustrates the difference between typical WAP architecture and the client server model. Under the client server web architecture model, the client 110 and web server 112 are linked directly by the network. Under typical WAP architecture, a WAP gateway 122 located between the access server 124 and the network server 126 functions as a proxy gateway. The WAP gateway 122 implements the WAP conversion functionality, converting non-secure data requests from binary wireless session protocol (WSP) to text WSP. Although this proxy is physically static, WAP application servers 124 may be located elsewhere, closer to the mobile terminal.
In a roaming scenario further limitations arise. Currently WAP roaming is based on a WAP gateway proxy at the home network site. FIG. 2 shows the typical WAP/circuit switched data (CSD) roaming architecture. The mobile unit, such as a WAP phone 210, is located in a visited public mobile network (VPMN). Network access is provided to the WAP phone 210 by a WAP gateway 212 physically located in the WAP phone 210's home public mobile network (HPMN). The WAP phone 210 is preconfigured to place a mobile operator CSD call according to the setup burned into it during production or by the network operator. A typical setup includes the following parameters:
Dial-up Number:+4113806777User Name:starAuthentication type:NormalPassword:homeHomepage:http://wap.starhome.comIP Address:190.190.10.170IP Port:9201Bearer:DataData call speed:9600Connection type:TemporaryConnection Security:OffInactive/idle timeout:300Response time:150Dial type:ISDNShow images:Yes
The call flow begins with an international data telephony connection initiated by a user agent such as a Mobile Switching Center (MSC) 214, to the dial-up number. After an optional authentication phase, the user receives a dynamically allocated HPMN private Internet protocol (IP)address from the Remote Access Server (RAS) 216 or from the Remote Authentication Dial-In User Service (Radius) server located in the home network. A Radius server is an authentication and accounting system used by many Internet Service Providers (ISPs). Radius is an unofficial standard used by many authorization servers to check that users accessing data services via ISPs have provided accurate information and to authorize device access to ISP systems.
Once the session is created, a Radius accounting packet is sent from the RAS 216 to the WAP gateway 212. This packet includes the dynamically allocated IP address and the user Mobile Station International Subscriber Directory Number (MSISDN). The user is recognized in the system in this phase. At the same time, the user agent receives its given IP address back at the phone and starts initiating requests.
Routing the call through the home network is costly to the user, as the roaming data user is obliged to pay long distance or international telephony charges in addition to any other charges for data services. However, in most cases, even that simple yet costly configuration does not work because digital calls are not supported internationally, whilst digital calls are the default setup for WAP access. Another difficulty may appear when MSISDN is required for authentication or billing by the RAS 216 or WAP gateway 212 while the calling line identifier (CLI) is not delivered over international links, such as ISUP/SS#7 links.
Additional problems arise when the phone is configured to dial a short code rather than an international number. Operators commonly use this setup for differentiated billing and/or network topology considerations, for example to ensure that users always access the physically closest RAS.
Additional drawbacks of the CSD architecture are inefficient access to data service applications, lower performance of these applications, and relevancy of the provided information. If the content server is local (in the VPMN or geographically close to the VPMN), a so-called tromboning scenario is created. The session is CSD tunneled to the HPMN and, after WAP conversion, returns to the VPMN through the Internet. If the application resides on a third domain, such as an international public land mobile network (IPLMN), the session is routed from the VPMN via the HPMN and then to the IPLMN, instead of directly from the VPMN to the IPLMN. In either case, the information provided to the user is not oriented to visitors and is not updated according to the visitor's current location and needs. In some cases, such as traffic, weather, and local activities, the information may be irrelevant.
General Packet Radio Service (GPRS) mobile operators, while not suffering from the same routing difficulties facing CSD mobile operators, have difficulty providing convenient data service access to their subscribers. Subscribers are routed to a single site, and cannot access a wide variety of data services through the mobile operator.
A need exists for a cellular data communication method that will provide roaming users with seamless access to data services throughout the accessible data network, and which will provide roaming users with relevant information based on both their current location and home network. The method should also ensure that the data communication is efficiently routed.